#include <iostream>
using namespace std;


// 函数常见样式：
// 1、无参无返
void test1()
{
    cout << "this is test1" << endl;
}

// 2、有参无返
void test2(int a)
{
    cout << "this is test2: a = " << a << endl;
}

// 3、无参有返
int test3()
{
    cout << "this is test3" << endl;
    return 999;
}

// 4、有参有返
int test4(int b)
{
    cout << "this is test4: b = " << b << endl;
    return b;
}

int main()
{
    //无参无返的函数调用
    test1();

    //有参无返的函数调用
    test2(100);

    //无参有返的函数调用
    int num1 = test3();
    cout << "num1 = " << num1 << endl;

    //有参有返的函数调用
    int num2 = test4(187);
    cout << "num2 = " << num2 << endl;
    
    return 0;
}